The uveitides are a collection of ~30 distinct diseases characterized by intraocular infection. Each disease has its own features, course, treatment, and prognosis. Traditionally, the uveitides have been grouped by the primary anatomic site of inflammation as anterior uveitis, intermediate uveitis, posterior uveitis, and panuveitis. However, there are substantial limitations to this lumping of diseases. For example, among the posterior uveitides, some (e.g. toxoplasmic retinitis and cytomegalovirus retinitis) are infectious and require treatment with antimicrobial/antiviral agents, some are chronic, presumed immune-mediated diseases that require immunosuppression (e.g. birdshot chorioretinitis, multifocal choroiditis, serpiginous choroiditis), and a few are self-limited, spontaneously-remitting diseases with a good prognosis (e.g. acute posterior multifocal placoid pigment epitheliopathy and multiple evanescent white dot syndrome). As such precise diagnosis is critical for research, including epidemiology, translational pathogenesis research, outcomes research, and disease specific clinical trials. Classification criteria are a type of diagnostic criteria used for reserch purposes. Although classification criteria seek to optimize sensitivity and specificity, when a trade-off is required, they emphasize specificity in order to ensure that a homogeneous group of patients is being studied. A precise phenotype is required particularly for genomic risk factor studies of complex disorders and translational pathogenesis research, as inclusion of other diseases with different risk factors and disease mechanisms would confound the results. Currently there are no widely-accepted and validated classification criteria for any of the uveitides. Preliminary data indicate fair to moderate agreement at best on the independent diagnosis of any one case by uveitis experts (?'s 0.27-0.40), but the ability of committees to reach agreement on the diagnosis of >98% of cases. The goal of the Developing Classification Criteria for the Uveitides project is for the Standardization of Uveitis Nomenclature (SUN) Working Group to develop classification criteria for the 25 leading uveitides using a formal, rigorous approach. There are 4 phases to the project: 1) informatics, to develop a standardized terminology; 2) case collection, to develop a preliminary database of ~250 cases of each disease; 3) case selection, to select at least 150-200 cases of each disease that are generally accepted to be the disease (using formal consensus techniques) from the preliminary database into a final database; and 4) data analysis, using machine learning approaches, of the final database to develop a parsimonious set of criteria for each disease that minimizes misclassification. The informatics and case collection phases of the Project are complete. The case selection phase is well underway and uses online voting and consensus conference calls to achieve supermajority acceptance on all cases included in the final database. The goals of this application are to complete case selection and data analysis and develop classification criteria for the 25 of the major uveitides. These results are crucial to future clinical research i the field of uveitis.